Dresden 2014 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 39: Liquid and Amorphous Metals I - Shearbands
MM 39.5: Talk
Wednesday, April 2, 2014, 11:15–11:30, IFW A
Boson peak in the heat capacity of severely deformed metallic glass — Jonas Bünz1, •Tobias Brink2, Koichi Tsuchiya3, Gerhard Wilde1, and Karsten Albe2 — 1Institut für Materialphysik, Westfälische Wilhelms-Universität Münster, Germany — 2Institut für Materialwissenschaft, Technische Universität Darmstadt, Germany — 3National Institute of Materials Science, Sengen, Tsukuba, Japan
Heat capacity measurements on amorphous materials reveal an additional contribution to the low temperature heat capacity compared to crystalline materials. This so called boson peak, which is due to additional vibrational modes, appears as an excess heat capacity compared to the Debye T3-law. We show the influence of deformation and annealing on the boson peak of Cu-Zr-based metallic glass using differential scanning calorimetry. To elucidate the origin of the changes of boson peak intensity, we utilize molecular dynamics computer simulations and the harmonic approximation. The results indicate that the emergence of shear bands and their gradual relaxation upon annealing strongly influence the intensity of the boson peak for the whole sample. Moreover, the annealing experiments also give new insights into the thermal relaxation behavior of shear bands in metallic glasses.